Analysis of Triple Band Rejected Compact Planar Octagon shape Monopole Antenna for UWB Applications

摘要

This paper presents a new design of ultra-wideband band (UWB) antenna with triple-band rejection characteristics and size miniaturization approach. The proposed antenna consists of a unique patch of octagon-shape connected to 50 Ω microstrip feed line on a top plane in addition to the partial ground on bottom plane. The patch tapering results in bandwidth (BW) improvement. It works efficiently over the impedance BW of 2.8 13 GHz, which gives Fractional Bandwidth (FBW) of 129% that covers the entire UWB band. It provides nearly an omnidirectional radiation pattern, has good realized gain and impedance matching. The proposed antenna has been designed with compact dimensions of 22mm × 32mm × 1.6mm, dielectric constant (Ɛr) of 4.4 and tangent loss of 0.02. For some wireless applications, the UWB systems suffer due to strong narrowband signal interference from unlicensed (ISM band) wireless communication devices. To avoid this interference, the patch inbuilt band rejection characteristics should be required. The proposed antenna has been designed with triple-band rejection capability that efficiently avoids WI-MAX, WLAN and X-band. The inverted T-stub is etched on patch radiator to reject WI-MAX (3.3–3.7 GHz), single C-strip pair besides feed line is used to reject WLAN (5.15-5.85 GHz) band and I-slot is used to reject satellite communication channel X-band (6.8-8.8 GHz) band. The antenna output performance has been measured in terms of simulated reflection coefficient and VSWR.